1. Field of the Invention
This invention relates to electrical connectors, and more particularly to an electrical connector having a push-on style interface, which can be snapped into a mounting hole of a panel and which has axially floating contacts.
2. Description of the Related Art
Coaxial cable connectors having a mounting configuration commonly known as “snap-in, float-mount” are used with push-on style interfaces such as a subminiature push-on (“SMP”) interface and a SMP-miniature (“SMPM”) interface, as described in MIL-STD-348A. A snap-in connector must easily and reliably snap into a mounting hole of a panel and lock itself in the mounting hole. A snap-in mechanism holds the connector body axially aligned so that it will be in a correct position to mate with a mating connector. The snap-in function of known prior art connectors is accomplished by one of several different mechanisms. A snap-in, float-mount connector has a front end for mating with the mating connector and a back end for connecting with a coaxial cable. A central portion of the snap-in, float-mount connector floats axially back (to the right in the Figures). A snap-in, float-mount mechanism allows the connector to be mounted to a panel by snapping the connector into a mounting hole, and, thereafter, allows a central portion of the connector to float axially in order to take up tolerance differences when a plurality of such connectors—each mounted in separate mounting holes of a single panel—are nearly simultaneously mated to a plurality of mating connectors. The float-mount function of known prior art connectors is usually accomplished by a compression coil spring.
FIGS. 1–3 show a first prior art connector 100 that utilizes a C-shaped retaining ring 101 mounted in a groove 102 in a ferrule 103 to achieve the snap-in function. FIG. 1 shows a perspective view of the first prior art connector 100. FIGS. 2 and 3 are cross-sectional views of the first prior art connector 100 through cut-line 2—2. The cross-sectional views of the first prior art connector 100 are simplified in that the internal components are not shown. FIG. 2 shows the first prior art connector 100 with a C-shaped retaining ring in a proper position. When operating as intended, the C-shaped retaining ring 101 closes as the first prior art connector 100 is pushed into a mounting hole in a panel (such as the panel 701 shown in FIG. 7) to allow it to slide through the mounting hole. After insertion, the C-shaped retaining ring 101 snaps open and locks the ferrule 103 into the mounting hole. Disadvantageously, it is easy for the relatively flimsy C-shaped retaining ring 101 to become out of proper position. FIG. 3 shows a first way that the C-shaped retaining ring 101 can be out of proper position. In FIG. 3, the dislodged C-shaped retaining ring 101 is out of the groove 102 and moved rearwardly. The first prior art connector 100 cannot be installed if the C-shaped retaining ring 101 is in the position shown in FIG. 3. FIG. 3A shows a second way that the C-shaped retaining ring 101 can be out of proper position. In FIG. 3A, the C-shaped retaining ring 101 is at the groove 102, but is moved down within the groove, and is no longer centered on the first prior art connector 100. When the C-shaped retaining ring 101 is in the position shown in FIG. 3A, the first prior art connector 100 cannot easily be installed by hand. When the C-shaped retaining ring 101 is in the position shown in FIG. 3A, a tool must be used to install the first prior art connector 100. The tool is needed to produce a greater force required overcome the obstruction caused by a portion of C-shaped retaining ring 101 protruding from the groove 102. Before installing the first prior art connector 100 by hand, the C-shaped retaining ring must be first properly re-positioned to the position shown in FIG. 2, also by using a tool. Another disadvantage of the first prior art connector 100 is that the C-shaped retaining ring 101 is mechanically weak and may degrade the reliability of the snap-in function.
FIGS. 4–7 show a second prior art connector 400 that utilizes a prior art spring finger basket 401 with a washer 402 to achieve the snap-in function. FIG. 4 shows a perspective view of the second prior art connector 400. The prior art spring finger basket 401 includes a plurality of prior art spring fingers 403. FIGS. 5–7 are cross-sectional views of the second prior art connector 400 through cut-line 5—5. The cross-sectional views of the second prior art connector 400 are simplified by not showing the internal components. FIG. 5 shows the second prior art connector 400 with the washer 402 in a proper position. FIG. 6 shows the washer 402 disadvantageously out of proper position. The washer 402 can be pushed down inside the spring finger basket 401 by the force of a coil spring 404, which disadvantageously locks the plurality of prior art spring fingers 403 open and renders the snap-in mechanism inoperable. Under the loading from the coil spring 404, it is relatively easy for the washer 402 to be disadvantageously pushed rearwardly and moved under the prior art spring finger basket 401, as shown in FIG. 6, instead of being at the tips of the prior art spring fingers 403, as the washer should be, as shown in FIG. 5. If the washer is pushed down into the prior art spring finger basket 401 prior to installation in the panel 701, the second prior art connector 400 cannot be installed. Furthermore, if the washer is pushed into the prior art spring finger basket 401 subsequent to installation, the second prior art connector 400 cannot be uninstalled. Disadvantageously, with the second prior art connector 400, axial alignment with a mating connector is not always present. FIG. 7 shows the second prior art connector 400 and a portion of a panel 701 into which it is mounted, and shows that the second prior art connector is not perpendicular to the panel, and, therefore, the axis of the second prior art connector would likely not be co-linear with the axis of a mating connector (not shown). The mounting mechanism of the second prior art connector 400 allows the second prior art connector to easily become misaligned. The second prior art connector 400 lacks any means for maintaining its axis perpendicular with the panel 701, which is required when a plurality of such connectors are mated. The second prior art connector 400 also lacks a provision to reliably return its axis perpendicular to the panel 701 after having been displaced from the perpendicular. Another disadvantage of the second prior art connector 400 is that the prior art spring fingers 403 are straight, which concentrates all the internal stress at the base of each finger and which can lead to stress cracking and/or fingers breaking off.